Lixiang

Equivocation

The fallacy of equivocation occurs when the conclusion of an argument depends on the fact that a word or phrase is used, either explicitly, or implicitly, in two different senses in argument. Such arguments are either invalid or have a false premise, and in either case they are unsound. Examples:

Some triangles are obtuse. Whatever is obtuse is ignorant. Therefore, some triangles are ignorant.

Any law can be repealed by the legislative authority. But the law of gravity is a law. Therefore, the law of gravity can be repealed by the legislative authority.

We have a duty to do what is right. We have a right to speak out in defense of the innocent. Therefore, we have a duty to speak out in defense of the innocent.

A mouse is an animal. Therefore, a large mouse is a large animal.

In the first argument "obtuse" is used in two different senses. In the first premise it describes a certain kind of angle, while in the second it means dull or stupid. The second argument equivocates on the word "law." In the first premise it means statutory law, and in the second it means law of nature. The third argument uses "right" in two senses. In the first premise "right" means morally correct, but in the second it means a just claim or power. The fourth argument illustrates the ambiguous use of a relative word. The word "large" means different things depending on the context. Other relative words that are susceptible to this same kind of ambiguity include "small", "good", "bad", "light", "heavy", "difficult", "easy", "tall", "short", and so on.

To be convincing, an argument that commits an equivocation must use the equivocal word in ways that are subtly related. Of the three examples given above, only the third might fulfill this requirement. Since both uses of the word Ð''right' are related to ethics, the unalerted observer may not notice the shift in meaning. Another technique is to spread the shift in meaning out over the course of a lengthy argument. Political speechmakers often use phrases such as "equal opportunity," "gun control," "national security," and "environmental